Aircraft



July 2, 1946. E. A. STALKER AIRCRAFT Filed Oct. 13, 1945 IS Sheets-Sheet l July 2, 1946.

E. A STALKER AIRCRAFT Filed 001;. 13, 1943 3 Sheets-Sheet 2 IN l/EN T02 ATTORNEYS July 2, 1946. E. A. STALKER AIRCRAFT Filed Oct. 13, 1943 3 Sheets-Sheet 3 .m n n.

IN VENTOE ad/L/ M B WW1} J ATTORZIEY-S Patented July 2, 1946 UNITED STATES PATENT OFFICE smcam lldward s. Stalker, has our. men.

Application mm 18, me, Serial No. man

My invention relates to aircraft and more particlliiarly to wings employing boundary layer contro It is the principal object of the invention to provide an aircraft having boundary layer control in which a blower is provided for producing a flow through a wing slot. the control being arranged to efiect an increase in the pitch of the blades of the blower accompanied by a decrease in the pitch of the propeller blades at the time maximum lift is desired as in landing.

It is a turther object to provide a plurality oi such combinations of engine. blower and propeller, each having such a control in which adequate power is made available for driving the blower when it is desired to develop a high lift.

and in which the power absorbed by the propeller at this time is reduced so that the engine is not overloaded.

It is also an object to provide such a ontrol in which the engine is relieved of the load of the propeller making the full power of the engine available to drive the blower when maximum lift is desired.

It is also an object to provide an aircraft in which the wing is equipped with an adjustable flap and in which in response to the lowering of the flap to develop high lift, the pitch of the propeller blades is reduced so that only limited thrust is developed under increased engine speed and concurrently therewith the pitch of the blower blades is increased to provide more eflective boundary layer control.

Other objects and advantages will be apparent from the following description, the accompanying drawings, and the appended claims.

I accomplish the above objects by the means illustrated in the accompanying drawings in which- Fig. l. is a fragmentary plan view of an aircraft constructed in accordance with the present invention;

Fig. 2 is a schematic view of the propeller, engine and connecting parts Fig. 3 is a fragmentary sketch partly in section of the pitch changing device;

Fig. 4 is a fragmentary plan view oi another form of the invention;

Fig. 5 is a. section along the line 5-5 in Fig. 4;

Fig. 6 isa section along the line 6-4 in Fig. 5;

Fig. 'l is a fragmentary section along line 1-4 in P18. 6;

Fig. 8 is a fragmentary plan view of a further form 0! the invention;

P13. 9 is a vertical section on the line 99 of Fig. 8 with the nap in raised position; and

Fig. 10 is a view similar to Fig. 9 on a larger scale and with the flap lowered.

This invention is directed toward a means of applying boundary layer control to current designs of airplanes, and without substantial change in the fundamental engine-propeller ombina. tion. Thus in a radial engine and propeller arrangement the engine is ordinarily between the propeller and the blower and so it is diflicult to arrange for the propeller acting as a windmill to drive the blower as set forth in my U. 8. Patent No. 1,913,844. To run shaiting around the radial engine is too heavy, costly and complicated. Furthermore it a tractor propeller is used the wing portion back of the propeller is in a low velocity wind when the propeller is acting as a windmill.

In accordance with this invention the engine of each propeller-engine-blowerunit remains in position between the propeller and the blower, and controls are provided so that when it is desired to develop high lift as for landing, the load on the engine of the propeller is reduced or eliminated, and the pitch of the blades of the blower is increased, the available engine power thus being adequate for this purpose. The engine can simultaneously be speeded up to increase its output but this does not result in materially increased forward speed or propeller load since the propeller has either been disconnected or the pitch of its blades has been substantially reduced so that itdoes not develop any great thrust.

Referring now more particularly to the drawings the wing is i having the induction slot 2 in its upper surface. The blower 3 inducts air through the slot 2 to ontrol the boundary layer. The blower is driven by the gear train 4 of which gear I is flxed to the extended crankshaft 6 of the engine I.

The engine I drives the propeller 8 through clutch 8 which is hydraulically operated. The valve I0 controls the flow of fluid to and from the clutch. The tube ll conducts fluid under pressure from a suitable reservoir (not shown) to the valve ii. The other ducts l2 and I8 conduct fluid to and from the clutch. Duct l I returns the fluid to the reservoir.

The blade attitudes are changed by the mechanism l5 shown in detail in Fig. 3. The cylinder it houses the piston ll which is movable axially by the fluid pressure. The element It is splined to the propeller shaft II and rotatably borne on the piston l I so that the propeller can rotate relative to the cylinder. The element ll is connected 3 to the propeller blades 20 and 2| by the links 22 and 23, respectively at a proper distance from the blade axis so that in response to an axial movement of the piston Il, the pitch of the blades is correspondingly altered.

The flow of pressure fluid to the cylinder I6 is controlled by valve I50. and suitable tubes connected to the cylinder and to the pressure source similar to those employed for valve I0.

At the time of landing the pilot moves the rod 2| which operates the valve levers 25 and 2! through the rod 21 and bell crank 28. This movement changes valve lli so that fluid pressure is supplied to clutch 8 to effect disengagement thereof and concurrently therewith valve Ila is set to supply pressure fluid to cylinder It in such direction as to produce an increase in the pitch oi the blades. Thus the pitch or the propeller blades is increased and with the engine disconnected from the propeller, the latter is free to windmill but because of the increased pitch setting. it does not rotate at an excessive or dangerous speed.

The engine remains connected to the blower and the engine is then speeded up to drive the blower 3 at sufliclent speed to effect an adequate flow through the slot 2 to augment the lift of the wing for landing. Since there are a plurality of such engine blower combinations such as I and 2, and 1a and la, the failure of one engine or even several will not destroy the high lift obtained from the slot because additional power for this purpose can be supplied from the remaining engine or engines.

In another form oi the invention, Figs. 4 to 6, the blower is an axial flow type with blades adiustable as to pitch. During high speed operation the pitch oi the blades is small so that little power is consumed but at the time of landing it is desired to expend a relatively large amount 01' power in driving the blower. It is however undesirable to expend a large amount of power in the propeller 8 when landing for two reasons: first this power is not then available to the blower, and second if the propeller consumes much power it will produce a large thrust which is undesirable at landing. On the other hand the propeller ii ahead of the wing should retard the flow over the wing as little as possible. v

The invention is arranged so that the pitch of the propeller is suflicient for the propeller to produce only a small thrust and small increase in wind velocity over the wing. Then the propeller need not be disengaged from the engine. The operation of the mechanism to increase the pitch of the blower blades decreases concurrently the pitch or the propeller to the proper value for landing.

In Figs. 4 to 6 the wing is 29 and the induction slot is 80. The blower istl composed of the stator 32 and rotor 33. The latter is driven from the engine II by means oi the shaft ill and gears 38 and 31. The engine also drives the propeller B, a pitch changing device i! as above described being also incorporated in the drive.

The engine throttle 24a is operated by the pilot by means of a flexible push-pull element within tube "b. It is to be noted that the throttle is operable independently of the pitch changing able to do this so that for landing conditions full power of the engine can be directed to the blower 3! the blades of which are set for high pitch, while in high speed flight full power can be directed to the propeller with the pitch increased to provide eflicient propeller operation and with the pitch of the blades of the blower correspondingly reduced.

The rotor of blower 83 is composed of a plurality of blades 38 which are mounted in the hub 39 for rotation about their longitudinal axis,

Each blade has a crank arm which is articulated to a spider Iii by means of a ball ended rod 4| whose ball is socketed in the crank arm of the blades. A movement of the spider vertically will thus rotate the blades in the hub and change the pitch.

The spider is moved vertically by the pilot by means of cables 82 passing about-the sheave 42 which has internal threads mating with those on the block M. The latter is spllned to the housing It as shown at 46 providing for free axial movement of the block while preventing rotation thereof. The block carries internally thereof the ball bearing 41 which rotatably supports the shaft 48 fixed to the spider 40. when the sheave is rotated the block N is displaced vertically thereby raising or lowering the spider and altering the pitch.

The cable 12 is also connected to an end of the bell crank 50 which in turn is connected by rod ii to the valve its which controls the pitch change device i5. Thus the pilot controls the pitches oi the propeller and blower coincidentally, the connections being such that movement 01' the control in one direction causes reduction of the blower pitch and an inverse change or an increase in the pitch of the propeller.

The air inducted through the slot 2 is discharged irom the opening I! in the bottom 0! the nacelle 53.

During normal flight condition the pilot's control is set to produce a relatively high pitch suitable Ior high speed flight, the pitch of the blower blades being reduced to a low value such that the major part of the power is available for the propeller.

When the airplane is to he landed the control is adjusted so that the propeller 8 is given a very low pitch so that little thrust is created and yet large enough so that there is no reduction of the wind velocity but actually a slight increase behind the propeller. Concurrently the pitch of the blower blades is increased and the engine power is in major part available to drive the blower so that maximum lift is developed.

In the form of the invention shown in Figs. 8, 9, and 10 the control of the pitches oi the blower and propeller is related to the operation of the flap ll which is hinged at N to the main body of the wing ID. The link 51 connects the flap to the pushrod Bl whose spanwise movement displaces the end of the link rearward. moving the flap down. The propeller pitch changing mechanism ll previously described is operatively connected to rod I8 by the bell crank 88 and link '0.

The pitch of the blower Ii is changed by means of the cables 12 as previously described. but the change is initiated by the movement of the iiap. A gear sector I is fixed to the flap 54 within the naceile ll so that the hinge axis or the flap is the axis of the gear sector. A pinion I2 meshes with the gear sector and carries fixed to itself the pulley II. when the flap is depressed the pulley I2 is rotated by the gear action, pulling cable 42 and thereby increasing the pitch of the blades or the blower. This causes a large flow through the wing slot 84 giving a large increase in lift capacity to the wing in coordinated relation to the flight conditions established by the lowering of the flap. The wing slot itself may have a uniform width throughout a major portion or even its entire range of movement and may also be arranged to provide a greater width as the flap is lowered. Through the interconnected relation with the pitch change mechanism for the propeller, the operation of lowering the flap also results in reducing the pitch of its blades so that it will not absorb power and develop a thrust unnecessarily. Conversely, upon the raising of the flap, the pitch of the blower blades is reduced and that of the propeller increased.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims,

What is claimed is:

1. In an aircraft of the character described, the combination of a wing having a slot in the surface thereof leading into the wing interior, a source of power within the aircraft, means for controlling the output of said power source, an adjustable pitch propeller driven from said power source, a blower, means for operating said blower from said power source throughout the range of 'pitch-adjustment of said propeller for inducing a flow through said slot to develop boundary layer control on said wing, said blower having adjustable pitch blades, and a single control means operable independently of said power controlling means for effecting concurrent reduction of pitch of the blades of said propeller and increase of pitch of the blades of said blower to make the power of said power source primarily available for operation of said blower in developing high lift on said wing.

2. In an aircraft of the character described, the combination of a wing having a slot in the surface thereof leading into the wing interior, a source of power within the aircraft, an adjustable pitch propeller driven from said power source, a blower also driven from said power source for inducing a flow through said slot to develop boundary layer control on said wing during normal flight thereof and over the range of adjustment of said propeller, said blower having ad-' .iustable pitch blades, 9, single means for varying inversely the pitch of said propeller blades and the pitch of said blower blades, and clutch means for disconnecting said propeller from said engine.

3. In an aircraft of the character described. the combination of a wing having a slot in the surface thereof leading into the wing interior, a source of power within the aircraft, an adjustable pitch propeller driven from said power source, a blower, means for operating said blower from said power source for inducing a flow through said slot to develop boundary layer control on said wing, said blower having adjustable pitch blades, a single means for varying inversely the pitch of said propeller blades and the pitch of said blower blades to make the power of said power source primarily available for operation of said blower in developing high lift on said wing, and means for controlling the power developed by said power source over substantially the entire range independently of the controls of the pitch of the blades of said propeller and said blower.

4. In combination, in an aircraft, a hollow wing having a slot in its upper surface in communication with the wing interior, an engine, an adjustable pitch propeller, a disengageable clutch to connect said propeller to said engine, a blower in communication with the wing interior, means operabiy connecting the blower to the engine to receive driving power therefrom, means for operating said clutch to completely disengage the propeller from the engine so that the power of said engine is available for driving the blower to induce a flow through said slot increasing the lift of the wing, and means operable concurrently with said clutch operating means for adjusting the pitch of the propeller to a large angle, said large pitch angle serving to restrain the propeller from rotating and retarding the flow across the wing.

5. In combination in an aircraft, a hollow wing having a slot in its upper surface in communication with the wing interior, an engine having a power shaft at opposite ends thereof, a blower operably connected to one of said power shafts to derive driving power therefrom and having adjustable pitch blades, said blower being in communication with the wing interior to induce a flow through said slot, a propeller, a. disengageable clutch to connect said propeller to the other a of said shafts opposite said blower shaft, and a common means to operate said clutch to disengage the propeller from the engine and coincidentally to increase the pitch of the blades of the blower to absorb engine power in developing a flow through said slot.

8. In combination in an aircraft, a hollow wing having a slot in its upper surface in communication with the wing interior, an engine having power shafts at opposite ends thereof, a blower having adjustable pitch blades and operably con-- nected to one of said power shafts to derive driving power therefrom, said blower being in communication with the wing interior to induce a how through said slot, an adjustable pitch propeller connected to one of said shafts opposite said shaft for said blower, clutch means for disconnecting said propeller from said engine and means coincidentally to alter the pitch amle of said propeller and blower.

7. In combination, a hollow wing having a flap, control means to depress said flap, said wing having a slot in its surface in communication with .the wing interior, a blower having adjustable pitch blades, a power source in continuous driving relation with said blower for operation thereof independently of the position of said flap said blower being in communication with the wing interior to induce a flow through said slot, and means controlled by movement of said flap for progressively adjusting the pitch of the blades of said blower to alter the pumping action of said blower in response to the movement of said flap.

8. In combination, a hollow wing having a slot in its upper surface and a flap, control means to depress said flap, an engine having power shafts at opposite ends thereof, means to control the power output of said engine, a blower having adjustable blades connected to one of said power shafts to derive driving power therefrom, said blower being in communication with said slot to induce a flow therethrough, means to alter the pitch angle of the blades of the blower, an adjustable pitch propeller connected to the power shaft opposite the shaft for said blower, and means operably connecting said flap control means to said blower and to said propeller ladscraft, a blower having adjustable pitch blades and 10 operably connected with said engine in both the raised and depressed positions of said iiap, said blower being in communicaton with said slot to induce a flow therethrough in both the raised and depressed positions or said flap, means to depress said flap, and means to change the pitch or the blades of said blower in direct response to movement or said flap.

EDWARD A. STAIBER.

Certificate of Correction Patent No. 2,403,133.

July 2, 1946.

EDWARD A. STALKER It is hereby certified that error appears in the printed-specification of the above numbered patent requiring correction as follows: Column 6 lines 29 and 30, claim 5, strike out a common and insert the same after and in has 46, claim 6; and that the said Letters Patent should be read wit h this correction therein that the same may conform to the record of the case in the Patent Offiee.

Signed and sealed this 5th day of November, A. D. 1946.

LESLIE FRAZER,

First Assistant Uommz'ssimwr of Patents.

craft, a blower having adjustable pitch blades and 10 operably connected with said engine in both the raised and depressed positions of said iiap, said blower being in communicaton with said slot to induce a flow therethrough in both the raised and depressed positions or said flap, means to depress said flap, and means to change the pitch or the blades of said blower in direct response to movement or said flap.

EDWARD A. STAIBER.

Certificate of Correction Patent No. 2,403,133.

July 2, 1946.

EDWARD A. STALKER It is hereby certified that error appears in the printed-specification of the above numbered patent requiring correction as follows: Column 6 lines 29 and 30, claim 5, strike out a common and insert the same after and in has 46, claim 6; and that the said Letters Patent should be read wit h this correction therein that the same may conform to the record of the case in the Patent Offiee.

Signed and sealed this 5th day of November, A. D. 1946.

LESLIE FRAZER,

First Assistant Uommz'ssimwr of Patents. 

